const arr = ['foo',1,NaN,false]
console.log(arr.indexOf('foo'))
console.log(arr.indexOf(NaN)) //indexOf 不能判断NaN
console.log(arr.indexOf(false))

console.log(arr.includes(NaN)) //true
console.log(arr.includes(false))

console.log(Math.pow(10,2))
console.log(10 ** 2)